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Secret No More: Spy Satellite Designer Reveals Life's Work (space.com)
68 points by bdr on Oct 15, 2011 | hide | past | favorite | 11 comments


I remember seeing a photo snapped by a 70s spy satellite that showed a guy lying on a beach and the time on his wristwatch clearly visible. _1970s_. Makes one really wonder where things are at now.


I suspect that was unlikely to have been a satellite shot - even the best resolutions I have seen claimed are still around 5cm to 10cm - which is nowhere near close enough to resolve the time on a wristwatch.

http://en.wikipedia.org/wiki/KH-8

http://en.wikipedia.org/wiki/KH-9_Hexagon


I should really try and find that book the photo was in. It could've been an U2 shot rather than a satellite one, but it certainly was an ultra high-altitude arial shot.


It should be a relatively simple problem of mechanics and optics. How big would the spy camera have to be to capture that level of detail? Assuming say, a budget of $500mil to 1bn per satellite.


Someone does a calculation in this discussion:

http://www.natscience.com/Uwe/Forum.aspx/physics/10830/Maxim...

That suggests that the max resolution from 850km (which does appear to be the relevant height) of a 4m as 10cm. So for 1mm resolution, which would be about right to resolve the time an a watch, you'd need at least a 400m mirror, probably much larger.

So $1 billion wouldn't be anything like enough.

[Apologies to anyone who actually knows about optics.]


...and atmospheric distortion. That's a much harder problem, although there have been innovations there, as well - some of which have been applied by astronomers to improve the imagery of ground-based telescopes (e.g., digitally processing images based on the observed distortion of a reference image, such as a simple laser from a geosynchronous orbit captured at the same moment).


ISTR that the SR71 spyplane had large optics that had to loaded by a sled / fork truck and was capable of excellent resolution. See http://www.wvi.com/~sr71webmaster/sr_sensors_pg1.htm for example.


I've seen that photo too, maybe 20 years ago, and although I don't remember where it was anymore, I believe it was a mockup made for a magazine, and not a real satellite photo.


I would assume technology now allows them to cover huge areas, not just resolution. Basically if you are outside, assume you are being recorded.

Combine that with warrantless tracking of all cellphone ids and they know who they are looking at. It's just a question of how long they save the data and the fact that agencies don't usually talk to each other so data isn't shared only out of apathy.


By my math, there was only enough film in the satellite for five hours of continuous shooting. So I guess it sat dormant most of the time, and was only activated when there was serious intelligence need?


well the video said up to 70 inches per second and there were 4 film recovery bays that would eject the pods of undeveloped film for a midair recovery by a plane.

Assuming the video is correct and that the article is wrong, that would be ~15 hours per roll of film for a total of around 60 hours of continuous shooting.

I would imagine that they only used it for short bursts of filming to get high value places of interest.




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